Add the node reserved memory percentage
Add the node reserved memory percentage

This patch adds the node attribute “reserved memory percentage” that is
derived from the maximum reserved memory for a node and its total
memory.

This will be useful for enhancing the balancing algorithm.
mbakke/ganeti,andir/ganeti,yiannist/ganeti,apyrgio/snf-ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,apyrgio/snf-ganeti,ganeti/ganeti,ganeti/ganeti,apyrgio/ganeti,yiannist/ganeti,mbakke/ganeti,bitemyapp/ganeti,bitemyapp/ganeti,onponomarev/ganeti,apyrgio/ganeti,onponomarev/ganeti,leshchevds/ganeti,dimara/ganeti,yiannist/ganeti,leshchevds/ganeti,andir/ganeti,ganeti-github-testing/ganeti-test-1,dimara/ganeti,grnet/snf-ganeti,andir/ganeti,grnet/snf-ganeti,mbakke/ganeti,leshchevds/ganeti